Digital duplication of images using encoded data

ABSTRACT

A reader and printer system is provided that is capable of reading data from a substrate, decoding the data and printing information derived from the data. The data is carried on the substrate as an array of dots. The substrate carries an image and the data is a digital representation of the image and so a digital copy of the image may be made from the data carried on the substrate.

[0001] Continuation Application of U.S. Ser. No. 09/693,317 filed onOct. 20, 2000

CO-PENDING APPLICATIONS

[0002] Various methods, systems and apparatus relating to the presentinvention are disclosed in the following co-pending applications filedby the applicant or assignee of the present invention simultaneouslywith the present application:

[0003] US Patent Application Serial Number

[0004] Ser. No. 09/693,471

[0005] Ser. No. 09/693,083

[0006] Ser. No. 09/693,134

[0007] Ser. No. 09/693,078

[0008] Ser. No. 09/693,226

[0009] The disclosures of these co-pending applications are incorporatedherein by reference.

[0010] Various methods, systems and apparatus relating to the presentinvention are disclosed in the following co-pending application filed bythe applicant or assignee of the present invention on Jul. 10, 1998:

[0011] U.S. Ser. No. 09/112,781

[0012] U.S. Ser. No. 09/112,785

[0013] U.S. Ser. No. 09/112,824

[0014] The disclosures of these co-pending applications are incorporatedherein by reference.

[0015] Various methods, systems and apparatus relating to the presentinvention are disclosed in the following co-pending applications filedby the applicant or assignee of the present invention on Jun. 30, 2000:

[0016] U.S. Ser. No. 09/608,308,

[0017] U.S. Ser. No. 09/608,779,

[0018] U.S. Ser. No. 09/607,987,

[0019] U.S. Ser. No. 09/608,776,

[0020] U.S. Ser. No. 09/607,250

[0021] U.S. Ser. No. 09/607,991,

[0022] The disclosures of these co-pending applications is incorporatedherein by reference.

FIELD OF THE INVENTION

[0023] The present invention relates to an apparatus for printing out orduplicating photographs from information recorded in infrared ink on thetop of the photograph using an ink jet printing system.

BACKGROUND OF THE INVENTION

[0024] The applicant has previously described in U.S. Ser. No.09/112,785 method and apparatus for printing out images using an ink jetprinting system on a print media using a pagewidth ink jet printhead.The image can also be transformed by an image processing program loadedinto the camera system for providing various effects on the image. Theapplicant has also disclosed recording data on the back of a printedphotograph which can be used to reprint or recover the image which isprinted on the front of the print media sheet. Such a printing systemrequires that there are two printheads one for printing the image itselfand one for printing the data in an encoded fault tolerant form on theback of the photograph.

[0025] In applicant's U.S. Ser. No. 09/112,824, a method and apparatusfor reproducing a photograph for example, printed using a camera systemsuch as disclosed in U.S. Ser. No. 09/112,781 or U.S. Ser. No.09/112,785 is disclosed.

[0026] In EP 354,581, a music score is encoded as a matrix of dots alonga margin on a sheet and the data is read by a linear scanner. Thescanner reads the width of the matrix which is much less than the widthof the music score sheet. The amount of data encoded and thereforerequiring processing is limited. Eight rows of binary data are used torecord the music score in a 12 row matrix. The scanner is hand held andreading the data can result in errors if the angle of the linear scanneris too large such that the width of the scanner does not fully cover thewidth of the matrix. The invention disclosed in EP 354,581 has limiteduse and the disclosure does not suggest itself to use with a credit cardsize data card (e.g. 55 mm×85 mm) as disclosed in U.S. Ser. No.09/112,781.

[0027] In the article, “Optical Sheet Memory System”, Shinji Ohyama,Electronics and Communications in Japan, Part 2, Vol. 75 No.4, 1992, pp73-85, a system for recording a number of images and a duration of soundon a postcard size sheet using printed dots is disclosed. Postcards aremass-produced using a “precision printing method” the substance of whichis not described. This system while similar to applicant's U.S. Ser. No.09/112,785 or U.S. Ser. No. 09/112,824 does not provide for a portableon-demand print imaging system nor does it provide an output with both aviewable image and an encoded recoverable form thereof. The postcard isunusable without a data reader.

[0028] The applicant has disclosed in co-pending applications U.S. Ser.No. 09/693,471, U.S. Ser. No. 09/693,083 and U.S. Ser. No. 09/693,134filed concurrently herewith, methods for recording data relating to animage captured by a camera system on top of or coincident with theprinting of the image itself, that is, the image and the data arerecorded on the same side and in the same area of the print media. Sucha method requires a pagewidth ink jet printhead having at least four inkjet nozzles per printed “dot”, three for printing the color image namelyfor printing with cyan, magenta and yellow inks and one for printingwith an infra-red ink for printing the data corresponding to the imageafter it has been processed into an encoded fault tolerant digital form.

SUMMARY OF THE INVENTION

[0029] In one broad form the invention provides an apparatus for readingdata encoded as an array of dots carried on a substrate, the array beingsubstantially invisible to an average unaided human eye, the apparatusincluding:

[0030] a detector that detects the array of dots on the substrate andoutputs a first signal representative thereof;

[0031] a decoder interconnected to said detector that receives anddecodes said first signal to produce a second signal corresponding tothe first signal; and

[0032] a printer that prints information derived from said second signalonto media.

[0033] The detector may detect the array of dots optically and if so theapparatus may include a light source that illuminates the substrate withlight whilst the detector is detecting said array of dots.

[0034] The dots are preferably dots of ink and more preferably the inkis infrared absorbing ink with little absorption in the visiblespectrum. When a light source is provided, preferably the light sourceilluminates the substrate with infrared light whilst the detector isdetecting said array of dots.

[0035] The apparatus may include a feeder mechanism that moves thesubstrate past the detector.

[0036] The data may be encoded using a Reed-Solomon process and theapparatus may include a Reed-Solomon decoder that decodes data encodedwith a Reed-Solomon process.

[0037] The information printed by the printer may include the data. Thesubstrate may carry an image and the data may include a digitalrepresentation of the image. The information printed may include theimage and the data.

[0038] If the information printed includes the data, preferably the dataprinted by the printer is encoded as an array of dots, the array beingsubstantially invisible to an average unaided human eye

[0039] The present invention seeks to provide an apparatus for decodingthe data printed on a photograph and printing out an image decoded fromsaid data on a print media. The data printed on top of the image may bea digital representation of the image itself in an encoded faulttolerant digital form, or the image so encoded and an image processingprogram for producing a particular effect upon the image, or two images,one being the image per se and the other being the image as transformedby an image processing program. In the former case the image itself canbe printed out notwithstanding substantial damage to the print mediaupon which the image and the encoded image data is recorded. In thesecond case the image can be printed out in its original form or asmodified by the image processing program recorded along with that imagedata. In the third case either the image per se or the image astransformed can be printed out. The data which is recorded on thephotographic image is encoded in such a way that even if substantialdamage occurs to the surface of the photograph, the data will allowrecovery of the image. This is possible by suitable duplication andredundancy in the data compression and scrambling of the data andencoding the data in a fault tolerant, for example a Reed-Solomon, codeform. The size of the photograph is approximately 4″×6″ (102 mm×152 mm).The data can be recorded on substantially the whole area of thephotograph in a variety of formats, one of which is to record it as aseries of data blocks (the so-called “alternative Artcard” format) andanother of which is to record the data continuously over the data areaas a series of columns (the so-called “Artcard” format) both of whichare described in detail in U.S. Ser. No. 09/112,781 or U.S. Ser. No.09/112,785. The former method of encoding, described in applicant'sco-pending applications U.S. Ser. No. 09/693,471, U.S. Ser. No.09/693,083, U.S. Ser. No. 09/693,134, would allow recovery of the imageeven if one third of the data blocks were damaged. Other sizes of printmedia are also disclosed for example a panoramic print which isapproximately the same height but twice the width of the standard print4″×6″ described above.

[0040] By having the image data recorded on the image itself the need tohave a separate photographic negative and to store it along with thephotograph is avoided. Presently, the storage of image data in a digitalform is on a computer system and is subject to the limited capacity ofthe hard drive, the ability to find the data and the risk of damage tothe hard drive storing the data, the obsolescence of the hard drive, orthe obsolescence of the image data format. These defects are avoided inthe current arrangement whereby the data is recoverable if thephotograph itself is available, if it has not suffered more than onethird damage, that is approximately two thirds is available forprocessing.

[0041] It is an object of the present invention to provide for anapparatus of reading digital data printed on a photograph in infraredink wherein the data is encoded image data from a camera system, theapparatus including a scanner means for scanning data in infraredprinted on the photograph; means for advancing the print media throughthe scanning means; means for illuminating the print media with infraredradiation; means for processing data output from said scanner meansincluding means for decoding said data; ink jet printer means forprinting out the image derived from said decoded data on a print mediaattached to said ink jet printer means.

[0042] The encoded fault tolerant digital data may also be reprinted ontop of the recovered or replicated image if the ink jet printhead hasprovisions for printing in the necessary number of colors, namely cyan,magenta, yellow and infrared. If the photograph is undamaged then adirect copying or replication of the infrared data and/or color imagecan be produced in the manner of the applicant's method and apparatusdisclosed in the application U.S. Ser. No. 09/112,824. If the photographis damaged then the full data would have to be recovered before beingprinted and, if required encoded again into its fault tolerant digitalform for print out simultaneously with the image on the print media.Other versions of the image can also be printed if the apparatus isprovided with means for reading an “Artcard” and for processing the datareceived therefrom in the manner as described in U.S. Ser. No.09/112,781 and U.S. Ser. No. 09/112,785 by the applicant. In thisinstance, the Artcard reader may be the same device as the photographscanning means or may be a separate integer. An Artcard as disclosed insaid applications is of a credit card size approximately 55 mm×85 mm andthe scanning means for scanning a photograph as required for the presentinvention would be wider to accommodate the 102 mm×152 mm (4″×6″) sizeof the photograph. In that case, the scanner means may be provided withmeans for accommodating various width cards for example, for alteringthe size of the slot through which the Artcard or the photograph is tobe inserted.

[0043] The print media used to print out the recovered or duplicatedphotograph is the same as the photograph itself namely approximately 102mm×152 mm (4″×6″), although it is contemplated that the print media maybe of a larger size such as to provide a panoramic print of the sameheight but approximately twice the width of the standard photograph. Apanoramic print may require an image processing program to be employedusing the appropriate Artcard for that purpose or the originalphotograph may have been a panoramic print with the encoded dataincluding the necessary image processing program encoded therewith, forexample as described in the applicant's application U.S. Ser. No.09/693,083.

BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Notwithstanding any other forms which may fall within the scopeof the present invention, preferred forms of the invention will now bedescribed, by way of example only, with reference to the accompanyingdrawings in which:

[0045]FIG. 1 illustrates one form of card reader according to theinvention;

[0046]FIG. 2 illustrates an exploded view of FIG. 1;

[0047]FIG. 3 illustrates a side perspective view, partly in section, ofone form of construction of CCD reader unit;

[0048]FIG. 4 illustrates a checkerboard pattern with which the datasurface may be modulated;

[0049]FIG. 5 illustrates the reading process; and

[0050]FIG. 6 illustrates the steps necessary to decode data read in froma photograph.

DESCRIPTION OF THE PREFERRED EMBODIMENT

[0051] Dots

[0052] The dots printed on the photograph are in infrared ink over acolor image. Consequently a “data dot” is physically different from a“non-data dot”. When the photograph is illuminated by an infrared sourcehaving complementary spectral properties to the absorption or responsecharacteristics of the infrared (IR) ink the data appears as amonochrome display of “black” on “white” dots. The black dots correspondto dots were the IR ink is and has absorbed the IR illumination and“white” dots correspond to areas of the color image over which no IR inkhas been printed and reflecting the IR illumination substantiallyunattenuated or only partially attenuated. Hereinafter the terms blackand white as just defined will be used when referring to the IR ink dotsrecording data.

[0053] Data Card Reader

[0054]FIG. 1, illustrates one form of card reader 500 which allows forthe insertion of a photograph 9 for reading. FIG. 2 shows an explodedperspective of the reader of FIG. 1. The card reader is interconnectedto a computer system and includes a CCD reading mechanism 35. The cardreader includes pinch rollers 506, 507 for pinching an insertedphotograph 9. One of the rollers e.g. 506 is driven by a motor 37 forthe advancement of the photograph 9 between the two rollers 506 and 507at a uniform speed. The photograph 9 is passed over a series of infrared(IR) LEDs 512 which are encased within an IR transparent mould 514having a semi circular cross section. The cross section focuses the IRfrom the LEDs e.g. 512 onto the surface of the photograph 9 as it passesby the LEDs 512. From the surface it is reflected to a high resolutionlinear CCD 34 which is constructed to a resolution of approximately 4800dpi. The CCD reader includes a bottom substrate 516 and a top substrate514. In between the two substrates is inserted the linear CCD array 34which comprises a thin long linear CCD array constructed by means ofsemi-conductor manufacturing processes.

[0055] The surface of the photograph 9 is encoded to the level ofapproximately 1600 dpi hence, the linear CCD 34 supersamples thephotograph's surface with an approximately three times multiplier. Thephotograph 9 is further driven at a speed such that the linear CCD 34 isable to supersample in the direction of photograph movement at a rate ofapproximately 4800 readings per inch. The scanned CCD data is forwardedfrom the reader to processing unit 31 for processing. A sensor 49, whichcan comprise a light sensor acts to detect the presence of thephotograph 13.

[0056] Turning to FIG. 3, there is illustrated a side perspective view,partly in section, of an example construction of the CCD reader unit.The series of LEDs e.g. 512 are operated to emit infrared (IR) radiationwhen a photograph 9 is passing across the surface of the CCD reader 34.The emitted IR radiation is transmitted through a portion of the topsubstrate 523. The substrate includes a portion e.g. 529 having a curvedcircumference so as to focus IR radiation emitted from LED 512 to apoint e.g. 532 on the surface of the photograph 9. The focused IRradiation is reflected from the point 532 towards the CCD array 34. Aseries of microlenses e.g. 534, shown in exaggerated form, are formed onthe surface of the top substrate 523. The microlenses 523 act to focusIR radiation received across the surface to be focused down to a point536 which corresponds to a point on the surface of the CCD reader 34 forsensing of IR radiation falling on the IR sensing area of the CCD array34.

[0057] A number of refinements of the above arrangement are possible.For example, the sensing devices on the linear CCD 34 may be staggered.The corresponding microlenses 34 can also be correspondingly formed asto focus IR into a staggered series of spots so as to correspond to thestaggered CCD sensors. The CCD array may only cover a part of the widthof the photograph being scanned (for example, a half) and a microlensarray or other optical arrangement may be utilized to enable radiationfrom the full width of the photograph to be collected for detection.Suitable linear CCD arrays sensitive to infrared radiation are thoseused in facsimile machines or flat bed scanners. For a description ofthe construction and operation of linear CCD devices, reference is madeto a standard text such as in “CCD arrays, cameras and displays” byGerald C Holst, published 1996 by SPIE Optical Engineering Press.Further, suitable sensor devices are regularly described in the IEEETransactions on Consumer Electronics.

[0058] To assist reading, the data surface area of the photograph 9 ismodulated with a checkerboard pattern as shown with reference to FIG. 4.A portion of the data 25 is shown in schematic form and the datacomprises an array of IR dots which is additionally modulated by a highfrequency “checkerboard” pattern 21 added to the data so as to assist insensing of the encoded data. Other forms of high frequency modulationmay be possible however.

[0059] A printer is provided in combination with the scanner forprinting out the image data on the photograph after it has been read anddecoded. For example, the applicant's Artcard reader or an Artcam withan integral Artcard reader as disclosed in U.S. Ser. No. 09/112,785modified to accommodate reading in the infra-red of a wider and longercard and to which print means can be removably attached can be used forthese purposes.

[0060] A suitable printhead is disclosed in applicant's U.S. Ser. No.09/608,308, U.S. Ser. No. 09/608,779, U.S. Ser. No. 09/607,987, U.S.Ser. No. 09/608,776, U.S. Ser. No. 09/607,250, and U.S. Ser. No.09/607,991 applications, which disclose a 6-ink ink jet pagewidthprinthead for printing an A4 size page (210 mm×275 mm or 8″×11½″). Inthe current invention the photograph print media may be 4″×6″ (102mm×152 mm) requiring a printhead of approximately half the width asdisclosed therein.

[0061] Reading Data from the CCD—General Considerations

[0062] In what follows, it is assumed that the data is encoded on aphotograph using the so-called “Artcard” format as disclosed inapplicant's U.S. Ser. No. 09/112,781 or U.S. Ser. No. 09/112,785 in adata area of 97 mm×147 mm for a 102 mm×152 mm photograph (4″×6″) with2.5 mm borders (0.1″). In this format the data area is continuous andbordered by targets at the leading and trailing edges of the data areaand by other indicia along the top and bottom margins to ensure correctreading of the data notwithstanding up to 1° rotation of the photographwith respect to the linear CCD IR sensor's orientation. The data isscrambled and encoded using a Reed-Solomon algorithm or process. Inaddition, the data may be compressed before encoding and scrambling. Thedata may be image data from a camera system, image data and an imageprocessing program, or two images, one the image as photographed andanother an image as transformed by an image processing program such asdescribed in applicant's co-pending applications U.S. Ser. No.09/693,471, U.S. Ser. No. 09/693,083, U.S. Ser. No. 09/693,134.

[0063] As illustrated in FIG. 5, the reading process has 4 phasesoperated while the pixel data is read from the card. The phases are asfollows: Phase 1. Detect data area on photograph Phase 2. Detect bitpattern from photograph based on CCD pixels, and write as bytes. Phase3. Descramble and XOR the byte-pattern Phase 4. Decode data(Reed-Solomon decode)

[0064] The photograph 9 must be sampled at at least double the printedresolution to satisfy Nyquist's Theorem. In practice it is better tosample at a higher rate than this. Preferably, the pixels are sampled at3 times the resolution of a printed dot in each dimension, requiring 9pixels to define a single dot. Thus if the resolution of the photograph9 is 1600 dpi, and the resolution of the sensor 34 is 4800 dpi, thenusing a 100 mm width CCD image sensor (98.7 mm is required to cover thewidth of the data area of 97 mm×147 mm with margins of 2.5 mm printed at1600 dpi print resolution and allowing for up to a 1° rotation of aphotograph of 4″×6″ or 102 mm×152 mm) results in 18900 pixels per column(100*1600*3/25.4). Therefore if a photograph stores 8 MB of dot data (at9 pixels per dot) then this entails 8 MB*8*9/18900=30,476 columns orapproximately 30,500 columns. Of course if a dot is not exactly alignedwith the sampling CCD the worst and most likely case is that a dot willbe sensed over a 16 pixel area (4×4).

[0065] A photograph 9 may be slightly warped due to heat damage,slightly rotated (up to, say 1 degree) due to differences in insertioninto a reader, and can have slight differences in true data rate due tofluctuations in the speed of the reader motor 37. These changes willcause columns of data from the card not to be read as correspondingcolumns of pixel data. A 1 degree rotation in the photograph 9 can causethe pixels from a column on the photograph to be read as pixels acrossapproximately 305 columns.

[0066] Finally, the photograph 9 should be read in a reasonable amountof time with respect to the human operator. The data on the photographcovers most of the surface, so timing concerns can be limited to thedata itself. A reading time of approximately 3 seconds is adequate.

[0067] If the photograph is loaded in 3 seconds, then all 30,500 columnsof pixel data must be read from the CCD 34 in 3 seconds, i.e. 10,167columns per second. Therefore the time available to read one column is0.0000984 seconds. Pixel data can be written to a DRAM, for example of 8Mbytes one column at a time, completely independently from any processesthat are reading the pixel data.

[0068] The time to write one column of data to DRAM is reduced by usinga number of cache lines, for example, 8 cache lines. If 4 lines werewritten out at one time, 4 banks of DRAM can be written toindependently, and thus overlap latency reduced.

[0069] DRAM Size

[0070] The amount of memory required for reading and decoding of theencoded data is ideally minimized. The typical placement of a reader isin an embedded system where memory resources are limited, for example asa feature of an Artcam as described in U.S. Ser. No. 09/112,781 or U.S.Ser. No. 09/112,785. This is made more problematic by the effects ofrotation as the more the photograph is rotated, the more scanlines arerequired to effectively recover original IR dots.

[0071] There is a trade-off between algorithmic complexity, userperceived delays, robustness, and memory usage. One of the simplestreader algorithms would be to simply scan the whole photograph and thento process the whole data without real-time constraints. Not only wouldthis require huge reserves of memory, it would take longer than a readeralgorithm that occurred concurrently with the reading process.

[0072] The actual amount of memory required for reading and decoding aphotograph is twice the amount of space required to hold the encodeddata, together with a small amount of scratch space (1-2 Mbyte).

[0073] Decoding the data

[0074] A simple look at the data sizes shows the impossibility offitting the process into, for example, 8 MB of memory for example, asused in the applicant's Artcard reader of U.S. Ser. No. 09/112,781 ifthe entire pixel data (560 MB if each bit is read as a 3×3 array) asread by the linear CCD 34 is kept. For this reason, the reading of thelinear CCD, decoding of the bitmap, and the un-bitmap process shouldtake place in real-time (while the photograph 9 is traveling past thelinear CCD 34), and these processes must effectively work without havingentire data stores available.

[0075] The unscrambling process requires two sets of 8 MB areas ofmemory since unscrambling cannot occur in place.

[0076] It is assumed here that the data was encoded using the Artcardformat as described in U.S. Ser. No. 09/112,781 or U.S. Ser. No.09/112,785 with a checkerboard modulation. In the Artcard format, thedata is printed in a continuous data area the start and end of which ismarked by targets, for example 16 targets for a card of 55 mm×85 mm,each target having a white dot in the centre of an array of 31×31 blackdots with the data beginning 24 dots from that central dot. For a cardof 4″×6″ (102 mm×152 mm) size, 32 similar targets may be used.Alternatively, the data may have been recorded in the “alternativeArtcard” format which is equally disclosed in U.S. Ser. No. 09/112,785;or in U.S. Ser. No. 09/693,471, U.S. Ser. No. 09/693,083, U.S. Ser. No.09/693,134. In this format, data is arranged in data blocks havingspecific characteristics wherein the data blocks are locatable by adistinctive set of targets.

[0077] Turning now to FIG. 6, there is shown a flowchart 220 of thesteps necessary to decode the data. These steps include reading in thephotographic data 221, decoding the read data to produce correspondingencoded XORed scrambled bitmap data 223. Next a checkerboard XOR isapplied to the data to produce encoded scrambled data 224. This data isthen unscrambled 227 to produce data 225 before this data is subjectedto Reed-Solomon decoding to produce the original raw data 226.Alternatively, unscrambling and XOR process can take place together, notrequiring a separate pass of the data. Each of the above steps isdiscussed in detail in the applicant's applications U.S. Ser. No.09/112,781 or U.S. Ser. No. 09/112,785. As noted previously withreference to FIG. 5, the process of scanning data therefore, has 4phases, the first 2 of which are time-critical, and must take placewhile pixel data is being read from the CCD.

[0078] The four phases are described in more detail as follows.

[0079] Phase 1.

[0080] As the photograph 9 moves past the CCD 34 the start of the dataarea must be detected by robustly detecting special targets on thephotograph to the left of the data area. If these cannot be detected,the photograph is rejected as invalid. The detection must occur inreal-time, while the photograph 9 is moving past the CCD 34.

[0081] If necessary, rotation invariance can be provided. In this case,the targets, as described in applicant's U.S. Ser. No. 09/112,781 orU.S. Ser. No. 09/112,785, are repeated on the right side of thephotograph, but relative to the bottom right corner instead of the topcorner. In this way the targets end up in the correct orientation if thecard is inserted the “wrong” way. Phase 3 below can be altered to detectthe orientation of the data, and account for the potential rotation.

[0082] Phase 2.

[0083] Once the data area has been determined, the main read processbegins, placing pixel data from the CCD into a ‘data window’, detectingbits from this window, assembling the detected bits into bytes, andconstructing a byte-image in DRAM. This must all be done while thephotograph is moving past the CCD.

[0084] Phase 3.

[0085] Once all the pixels have been read from the data area, the motor37 can be stopped, and the byte image descrambled and XORed. Althoughnot requiring real-time performance, the process should be fast enoughnot to annoy the human operator. The process must take 8 MB of scrambledbit-image and write the unscrambled/XORed bit-image to a separate 8 MBimage.

[0086] Phase 4.

[0087] The final phase in the read process is the Reed-Solomon decodingprocess, where the 8 MB bit-image is decoded into a 4 MB valid imagedata area. Again, while not requiring real-time performance it is stillnecessary to decode quickly with regard to the human operator. If thedecode process is valid, the card is marked as valid. If the decodefailed, any duplicates of data in the bit-image are attempted to bedecoded, a process that is repeated until success or until there are nomore duplicate images of the data in the bit image.

[0088] The four phase process described requires 18 MB of DRAM. 8 MB isreserved for Phase 2 output, and 2 MB is reserved for scratch dataduring phases 1 and 2.

[0089] A description of the actual operation of each phase is providedin greater detail in U.S. Ser. No. 09/112,781 and U.S. Ser. No.09/112,785 for a data card 55 mm×85 mm and storing 2 MBytes of data.

[0090] If the data was encoded and printed on the photograph, using the“alternative Artcard” format, such as described in U.S. Ser. No.09/693,471, U.S. Ser. No. 09/693,083 or U.S. Ser. No. 09/693,134, thenthe procedure for reading and recovering the data is substantially asdescribed in applicant's applications U.S. Ser. No. 09/112,781 or U.S.Ser. No. 09/112,785.

[0091] Print Out Decoded Data

[0092] Once the data has been recovered, the image, the image astransformed by the encoded image processing program or either of these,depending on whether the data recorded on the photograph is, forexample, as disclosed in applicant's co-pending applications U.S. Ser.No. 09/693,471, U.S. Ser. No. 09/693,083 or U.S. Ser. No. 09/693,134,can be printed out using an ink jet printhead of the requiredcharacteristics. If only the image is to be printed a 3-ink ink jetprinthead will suffice. If the image and the encoded data is to beprinted then an at least 4-ink ink jet printhead would be necessary.

[0093] If the data can be stored either in the printer or in a RAM areaof the processor which decodes the encoded data then the printer can beprovided with means for enabling copies of the image to be printed asdesired, for example dedicated switches or at least a numeric keypad.Alternatively, if a number of copies is required, the photograph may bepassed repeatedly through the scanner.

[0094] The foregoing description has been limited to specificembodiments of this invention. It will be apparent, however, thatvariations and modifications may be made to the invention, with theattainment of some or all of the advantages of the invention. Forexample, it will be appreciated that the invention may be embodied ineither hardware or software in a suitably programmed digital dataprocessing system, both of which are readily accomplished by those ofordinary skill in the respective arts. Therefore, it is the object ofthe appended claims to cover all such variations and modifications ascome within the true spirit and scope of the invention.

1. An apparatus for reading data encoded as an array of dots carried ona substrate, the array being substantially invisible to an averageunaided human eye, the apparatus including: a detector that detects thearray of dots on the substrate and outputs a first signal representativethereof; a decoder interconnected to said detector that receives anddecodes said first signal to produce a second signal corresponding tothe first signal; and a printer that prints information derived fromsaid second signal onto media.
 2. The apparatus of claim 1 wherein thedetector detects the array of dots optically.
 3. The apparatus of claim2 including a light source that illuminates the substrate with lightwhilst the detector is detecting said array of dots.
 4. The apparatus ofclaim 1 wherein the dots are dots of ink.
 5. The apparatus of claim 4wherein the ink is infrared absorbing ink with little absorption in thevisible spectrum.
 6. The apparatus of claim 5 including a light sourcethat illuminates the substrate with infrared light whilst the detectoris detecting said array of dots.
 7. The apparatus of claim 1 including afeeder mechanism that moves the substrate past the detector.
 8. Anapparatus of claim 1 including a Reed-Solomon decoder that decodes dataencoded with a Reed-Solomon process.
 9. An apparatus of claim 1 whereinsaid information includes said data.
 10. An apparatus of claim 1 whereinthe substrate carries an image.
 11. An apparatus of claim 10 wherein thedata includes a digital representation of the image.
 12. An apparatus ofclaim 11 wherein the information printed includes the image and thedata.
 13. An apparatus of claim 12 wherein the data printed by theprinter is encoded as an array of dots, the array being substantiallyinvisible to an average unaided human eye